For the life of me I still don't understand what is meant by "rigged" primaries. No votes were changed. It just sounds like it was the debate scheduling, superdelegates committing long beforehand (which is irrelevant because Clinton still won by delegates), and a bunch of random talk among DNC staff that never amounted to anything. What else is there? This sketchy fundraising structure using states as pass through entities isn't right but it doesn't have anything to do with Bernie's votes.
This isn't to say the DNC wasn't being shady and untrustworthy, though. I'm just not sure I like the terminology here, because a lot of people seem to level charges on the DNC that describe something that wasn't happening. I can't tell you how many times I've seen people say the DNC actually stole the nomination from Sanders, when it is more like just working against him on the periphery.
All I can say is they really need to clean this mess up by 2020. Just let the candidates run on an even playing field, and stop trying to control everything. At the very least they should understand that they are too incompetent to tilt a primary against their disfavored candidates and get away with it.
At the end of the day when Hillary Clinton is in the center of the scandal you can’t scrub the appearance of corruption off. Any sort of context and nuance that takes longer than 15 seconds to explain is looked at with disdain and as lying. The best the Democrats can do is to move on and work on providing transparent primaries with even playing fields.